One possible aspect of the invention relates to a method for finding the position of a subscriber in a radio communications system.
In radio communications systems, arrangements with base stations and antenna devices are known, in which transmission signals from two or more subscribers are combined to form a transmission sum signal, and this transmission sum signal is passed by cables from the base station to at least two spatially distributed antenna devices for transmission. On the other hand, radio received signals from subscribers, which are received via the antenna devices, are combined to form a received sum signal, which is transmitted by cables to the base station.
When using glass fiber cables for cable transmission, the sum signals mentioned above are in general produced by analog modulation of a semiconductor laser.
Furthermore, methods are known for finding the position of a subscriber in a mobile radio communications system, which methods find the position of a subscriber via transceivers, with the aid of delay time measurements. Examples of this are position-finding methods in a GSM mobile radio system, based on the so-called “timing advance mechanism”.
However, a method such as this cannot be used in the radio communications system as described above, in which base stations are used with spatially distributed antenna devices, since multipath propagation and the reception situation mean that only ambiguous positions can be found. These ambiguities could be minimized only by using costly additional transceivers.